1. Field of the Invention
The invention relates to a method of fabricating a memory.
2. Description of Related Art
In general, the fabrication of self-aligned contact (SAC) openings is applied to overcome the increasingly shrinking line widths of memory and to avoid misalignment of the contact openings. In the fabrication of SAC openings, the thickness of the spacers on the sidewalls of the gates affects the size of the contact openings formed between the gates. However, since the memory device includes the memory region and the periphery region, and components such as gates in the memory region and the periphery region have different requirements for the thickness of the spacers, the fabrication becomes more complicated. Generally, a first set of spacers is formed simultaneously on each sidewall of the gates in the memory region and the periphery region. Thereafter, in order to form the source and drain region in the periphery region, a second set of spacers is usually formed on the first set of spacers of each gate in the periphery region. For the convenience of fabrication, the material of the second set of spacers is simultaneously filled into the openings between the gates in the memory region. After the source and drain region is formed in the substrate in the periphery region, the material of the second set of spacers in the periphery region and the material of the second set of spacers between the gates in the memory region are removed at the same time.
However, as the openings between the gates in the memory region have a high aspect ratio, it is difficult to remove the material of the second set of spacers between the gates completely. Moreover, the first set of spacers in the memory region may be damaged during the removal. Therefore, the first set of spacers cannot provide superior electrical insulation to the gates, and the size of the contact openings subsequently formed by adopting the first set of spacers is also affected.